Team Romney is taking the offensive on Medicare with a new ad that accuses President Obama of undermining the financial stability of the program.

The spot, titled “You Paid,” begins with a still photo of a concerned-looking white-haired guy. “You paid into Medicare for years, every paycheck,” says the narrator, while the camera moves in tighter on the shot.

Then there’s a quick cut to a photo of an empty wheelchair. “Now when you need it, Obama has cut $716 billion from Medicare. Why? To pay for Obamacare,” says the narrator. “So now the money you paid for your guaranteed health care is going to a massive new government program that’s not for you.”

Then a shot of a smiling Mitt Romney and his new running mate, Paul Ryan, appears. “The Romney/Ryan plan protects Medicare for today’s seniors and strengthens Medicare for the next generation,” it concludes.

If nothing else, the quick release of this ad shows that the Romney campaign knows it has to move fast to blunt Mr. Obama’s charge that Congressman Ryan wants to end Medicare as we know it. Plus, it picks up on talking points that some proponents of Ryan’s approach have been urging the GOP to use.

The first of these is obvious: that $716 billion slice out of the program’s funds.

To this Democrats would reply, "Yes, the Affordable Care Act did make that reduction. But the money was cut from Medicare payments to hospitals, Medicaid prescription drugs, and reimbursements to private insurance plans under the pilot Medicare Advantage program. It did not come directly from benefits."

(They might also add that both Ryan’s and Obama’s Medicare budgets foresee the same general financial path for the system. Both foresee per-person benefits rising at the rate of increase of the gross domestic product (GDP), plus 0.5 percent. The difference is in how the respective budgets plan to get to that financial goal.)

The second point the ad makes is simple, though made in a subtle way: Current recipients would not be affected by the Romney/Ryan team’s proposed changes. That’s why the ad says the pair would “protect Medicare for today’s seniors.”

That’s true. The Ryan-produced budget passed by the House earlier this year draws the line at age 55. Those 55 or older would not see any change in the Medicare system. Those under 55 would participate in Ryan’s “premium-support” model for the giant government health-care system.

“No one over the age of 55 would be affected in any way,” wrote Mr. Biggs.

But for people under age 55, Medicare would fundamentally change. “Premium support” means “voucher,” in the view of Democrats. Beneficiaries would receive a fixed sum of money from the government to buy private insurance from a Medicare Exchange. (The traditional fee-for-service would be one of the exchange’s options, and the premium would be adjusted for different regional costs and the health of the beneficiary.)

Democrats charge that under this system seniors would inevitably end up paying an increasingly large percentage of their health-care costs. Ryan’s proponents proclaim that’s not true. Competition for customers between private plans on the exchanges would effectively keep prices down, they say.

But is the Romney campaign smart to confront the issue in such a direct manner? After all, many GOP operatives worry that focus on Medicare diverts attention from the issues on which Obama fares worst among voters, the overall state of the economy and jobs.

Plus, Democrats have long “owned” Medicare, in the sense that polls show voters trust them rather than Republicans when it comes to the big program’s fate, notes George Washington University political scientist John Sides on the Monkey Cage political blog.

Such stereotypes are remarkably persistent, according to Mr. Sides. Political scientists’ research shows that when candidates try to “trespass” on the other party’s turf – when a Republican runs as pro-education, say, or a Democrat runs as tougher on defense – voters don’t really pay much attention.

Thus the Romney/Ryan ticket’s attempts to portray itself as the savior of Medicare “will be an uphill battle for the GOP,” he concludes.